On Mon, Mar 28, 2022 at 05:22:31PM +1100, Daniel Axtens wrote: > From: Patrick Steinhardt <p...@pks.im> > > Currently, all platforms will set up their heap on initialization of the > platform code. While this works mostly fine, it poses some limitations > on memory management on us. Most notably, allocating big chunks of > memory in the gigabyte range would require us to pre-request this many > bytes from the firmware and add it to the heap from the beginning on > some platforms like EFI. As this isn't needed for most configurations, > it is inefficient and may even negatively impact some usecases when, > e.g., chainloading. Nonetheless, allocating big chunks of memory is > required sometimes, where one example is the upcoming support for the > Argon2 key derival function in LUKS2. > > In order to avoid pre-allocating big chunks of memory, this commit > implements a runtime mechanism to add more pages to the system. When a > given allocation cannot be currently satisfied, we'll call a given > callback set up by the platform's own memory management subsystem, > asking it to add a memory area with at least `n` bytes. If this > succeeds, we retry searching for a valid memory region, which should now > succeed. > > If this fails, we try asking for `n` bytes, possibly spread across > multiple regions, in hopes that region merging means that we end up > with enough memory for things to work out. > > Tested-by: Stefan Berger <stef...@linux.ibm.com> > Signed-off-by: Patrick Steinhardt <p...@pks.im> > [dja: add this to the documentation at the top of mm.c > v2: fallback to non-contiguous] > Signed-off-by: Daniel Axtens <d...@axtens.net>
Reviewed-by: Daniel Kiper <daniel.ki...@oracle.com> Daniel _______________________________________________ Grub-devel mailing list Grub-devel@gnu.org https://lists.gnu.org/mailman/listinfo/grub-devel
